This invention is related generally to an optical display including a reflective color filter array (RFCA) liquid crystal display (LCD).
Color LCDs typically include a color filter array (CFA) mask which is used in generating color images. A broad range of colors may be achieved by spatially multiplexing each pixel into Red, Blue and Green colors (RGB) for example.
FIG. 1 illustrates an example of a typical color LCD with a color filter array. The color LCD 10 includes a substrate 12 having a light source 14, such as a gas discharge lamp. Light from the light source 14 is incident upon a display element 16 that acts to modulate the light in pixels. The display element 16 includes a liquid crystal layer 18 between two linear polarizers 20 and 22.
Regions of the liquid crystal layer 18 along with the polarizers 20 and 22 act as a light valve to selectively allow light to be transmitted from the light source 14 to the front of the LCD. For a normally black LCD, when a region of the layer 18 is turned on, such as by applying a voltage across the layer 18 at the region, light is allowed to pass through, otherwise light is blocked, and that pixel remains blocked. Thus, light may channeled through the different regions of the liquid crystal layer 18 by applying an appropriate voltage. Normally while LCDs are also known where the pixels pass light unless voltage is passed.
Color filters 24 of the CFA 26 are each disposed over discrete locations of the liquid crystal layer 18 (in a pixel pattern or mosaic). The filters are grouped as pixels to transmit the appropriate color light for the pixel. Each pixel typically comprises three subpixels (a triplet), where the filters corresponding to the subpixel transmitting red, green and blue light, respectively. Thus, each pixel includes a RGB (red, blue, green) triplet of filters.
The CFA 26 is shown in a side view with alternating filters 24r, 24b and 24g, which transmit red, blue, and green light, respectively.